Photodissociation processes of molecules and radicals involving multiple pathways and nonadiabatic crossings are studied using the photofragment imaging technique and the core-sampling version of time-of-flight spectroscopy. Capabilities and challenges are illustrated by two systems. The isocyanic acid system demonstrates how interactions among potential energy surfaces can change during dissociation. The hydroxymethyl photodecomposition system highlights Rydberg-valence interactions common in free radicals. The cross-fertilization between theory and experiment is emphasized.